Pyloric valve obstructing devices and methods

ABSTRACT

Methods, devices and systems facilitate intermittent and/or partial obstruction of a pyloric valve. Devices generally include a support portion for preventing the device from passing through the pyloric valve and a tissue engagement portion for contacting tissue adjacent the pyloric valve to obstruct the valve. Some embodiments also include a positioning member extending from the tissue engagement portion for helping position the device for obstructing the valve. A retaining member may optionally be included on the distal end of the positioning member for further maintaining a position of the device in the stomach. Some embodiments are deliverable into the stomach through the esophagus, either by swallowing or through a delivery tube or catheter. Some embodiments are fully reversible. Some embodiments self-expand within the stomach, while others are inflated or otherwise expanded.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/671,191 filed Sep. 24, 2003, and entitled “Pyloric ValveCorking Device and Method,” which claims priority to U.S. ProvisionalPatent Application Ser. No. 60/490,421, filed Jul. 28, 2003, andentitled “Pyloric Valve Corking Device and Method,” the full disclosuresof which are hereby incorporated by reference. This application alsoclaims priority to U.S. Provisional Patent Application Ser. No.60/525,105, filed Nov. 26, 2003, and entitled “Intragastric TherapeuticDevice and Method,” the full disclosure of which is hereby incorporatedby reference.

FIELD OF THE INVENTION

The present invention relates generally to medical devices and methods.More specifically, the invention relates to devices and methods forpartially and/or intermittently obstructing a pyloric valve to decreasegastric emptying, such as for treating obesity.

BACKGROUND OF THE INVENTION

Obesity has become a medical problem of epidemic proportions in theUnited States. Recent governmental studies estimate that as many as 40%of Americans are obese (defined as a Body Mass Index over 30), and ofthose, almost 20% are morbidly obese. Unfortunately, there is noindication that these percentages will decrease and every indicationthat they will increase in the coming years. Studies have linked obesityto countless health risks, a small sampling of which includescardiovascular disease, cancer, diabetes, orthopedic injuries andcomplaints, obstructive sleep apnea, chronic fatigue and depression.Despite billions of dollars spent searching for obesity cures,conducting research into nutrition and exercise, and educating thepublic about obesity, efforts to date have been largely ineffective.

Many Americans have tried combating obesity with diet, exercise and evenmedications, to no avail. Most people who lose weight through diet andexercise gain it back again in a short period of time. Availablemedications can have serious side effects, as was evidenced by therecent scare with the Fen-Phen dietary medication. Faced with thedifficultly of diet and exercise, nutritional information that seems tochange radically and rapidly, and diet medications and supplements thattypically do not work and may cause serious side effects, many obesepeople become frustrated and either decide to remain obese or choose topursue a more drastic treatment option.

The more drastic options typically involve surgical procedures, such asstomach stapling, other gastric reduction surgical techniques, placementof a constrictive band around the outside of the stomach, and gasticbypass. The most well known procedure, in part due to well-publicizedexperiences of celebrities like Al Roker and Carney Wilson, is thegastric bypass operation, known technically as a Roux-En-Y gastricbypass. In this procedure, the stomach is actually bypassed, and a verysmall stomach-like pouch remains, making a patient feel full afteringesting a small amount of food. Although gastric bypass can be highlyeffective, it is acknowledged to be a very high-risk operation, with a1-2% mortality rate, a number of possible complications such asdigestive problems, and a recovery period of up to 6 months. The othersurgical alternatives are also associated with either high risk, lowrate of effectiveness, or both.

Stemming from the high risks of gastric surgical procedures and theineffectiveness of diet and exercise for many obese people, a number ofmedical devices have been developed to address weight loss and obesity,but these too have numerous drawbacks. Some devices, for example, try tobypass a portion of the stomach or small intestine by essentiallycreating a tube or chute through which food passes without any nutrientsor calories being absorbed. Such devices are described, for example, inU.S. Pat. No. 5,820,584 and U.S. Patent Application Publication Nos.2003/0040804 and 2003/0109931. Unfortunately, these are designed tocause absorption problems in a patient, which may reduce intake ofcalories into the body but which also typically leads to “dumping” offood too rapidly through the digestive tract, leading to numerousgastrointestinal symptoms.

Another approach, as described for example in U.S. Patent ApplicationPublication No. 2003/0093117, involves performing a minimally invasivesurgical procedure on a stomach, typically to reduce its volume. Thedrawbacks with such approaches are that they are still relativelyinvasive and they are typically difficult or impossible to reverse.

Other techniques involve placing space-occupying balloons and otherdevices within the stomach to make the patient feel full after eatingsmall amounts of food. One such a device, for example, is described inU.S. Patent Application Publication No. 2003/0109935. Space occupyingdevices by themselves, however, may not be as effective as othertreatments, and many currently available devices have an unacceptablyserious risk of collapsing, passing through the stomach, and lodgingsomewhere in the intestines, thus causing a serious and potentiallyfatal intestinal blockage.

Yet another technique that has been attempted for treating obesityinvolves slowing down the rate at which food passes from the stomach,through the pyloric valve at the distal end of the stomach, and into theduodenum—i.e., the first part of the small intestine. Some researchershave found, for example, that stimulation of the gastric vagus nerve mayresult in reduced gastric motility leading to a loss of over 20% ofexcess weight in a nine month period. In another approach, severing thegastric vagus nerve may also be effective in treating obesity. Thesetherapies, however, require invasive, sometimes irreversible, surgicalprocedures, and may have adverse effects on the ability of the vagusnerve to perform other important functions.

Others have tried slowing gastric emptying by placing implants orinjecting bulking agents into tissue at or immediately adjacent thepyloric valve. Such techniques are described, for example, in U.S. Pat.No. 6,540,789 and U.S. Patent Application Publication Nos. 2003/0153806and 2003/0158601. In general, such methods have not been found to beeffective and, again, are often irreversible.

Therefore, because obesity is such an endemic and serious healthproblem, and because currently available treatment options are oftenineffective, extremely risky or both, a need exists for effective,relatively non-invasive treatments for obesity. Ideally, such treatmentswould be relatively easy to use and deploy in a patient and would helptreat obesity without a high risk of side effects or severecomplications. Such treatments would also ideally be reversible. Atleast some of these objectives will be met by the present invention.

SUMMARY OF THE INVENTION

The present invention provides devices, methods and systems forobstructing a pyloric valve to provide weight loss and in some casestreat or ameliorate obesity. Devices are generally delivered into thestomach where they expand or are expanded to partially and/orintermittently obstruct the pyloric valve. By partially orintermittently obstructing the pyloric valve, contents of the stomach(i.e., food) are retained longer in the stomach, thus causing a patientto feel full sooner and longer, and thus leading to reduced food intakeand weight loss.

A device is generally configured such that, upon placement in thestomach, it moves naturally to the pyloric valve and contacts tissueadjacent the valve to obstruct the valve opening. A portion of thedevice is configured to assure that the device cannot pass through thepyloric valve and into the intestine, while another portion of thedevice is configured to contact stomach tissue adjacent the pyloricvalve without damaging the tissue. During digestion and the naturalcontractions of the stomach, the device moves in and out of contact withthe valve such that gastric contents are allowed to pass through to thesmall intestine, but the rate of passage is slowed. In a number ofembodiments, a device may be introduced into the stomach either througha catheter device extending through the esophagus or by a patientswallowing the device. In some embodiments, the device may be retrievedand removed through the esophagus, often using the same device that wasused for delivery. In other embodiments the obstructing device maydissolve over time and pass harmlessly through the digestive tract.

In one aspect of the present invention, a device for obstructing apyloric valve of a stomach includes an expandable support portionadapted to expand in the stomach from a first configuration to a largersecond configuration, and a compliant tissue engagement portion coupledwith the expandable support portion and adapted to engage stomach tissueadjacent the pyloric valve to at least intermittently obstruct thepyloric valve. In the second configuration, the support portion preventspassage of the device through the pyloric valve. In general, the supportportion and the tissue engagement portion may have any of a number ofdifferent configurations. In one embodiment, the two portions are partof one, unitary extrusion, with the support portion having a greaterwall thickness than the tissue engagement portion and/or containing oneor more support members, such as support rings, lattices, frames or thelike. In other embodiments, the two portions may be separate piecescoupled together. The compliant tissue engagement portion generally issufficiently compliant so as to prevent or avoid injury (such aserosion) of stomach tissue with which the device comes in contact.

In some embodiments, though not in all, the expandable support portionis self-expanding, thus including at least one self-expanding material.For example, the self-expanding material may include but is not limitedto Nitinol, spring stainless steel or other shape-memory, super-elasticor spring-loaded materials. In some embodiments, the self-expandingmaterial includes at least one support member, such as but not limitedto one or more rings, coils, cages, struts, scaffolding, baskets, spokesor umbrellas. Such support members may be configured such that, onceexpanded, they prevent the device from collapsing and passing into theintestine. In some embodiments, the support portion includes one or moresupport members coupled with at least one material, such as ofGore-tex®, silicone, polyeurethane or polyethylene. The tissueengagement portion, in turn, may extend from the support portion and bemade of the same or different material, such as those just listed.

In alternative embodiments, the self-expanding material may include aself-expanding foam disposed within the expandable support portion andpossibly the tissue engagement portion as well. For example, the foammay comprise polyethylene foam, polyurethane foam, silicone foam or thelike. Like the support members just described, the expandable foam helpsprevent passage of the device through the pyloric valve. Optionally, insome embodiments, the self-expanding material expands upon contactingone or more substances naturally present in the stomach.

In some embodiments, the support portion and the tissue engagementportion comprise at least one of Gore-tex®, silicone, polyeurethane andpolyethylene, with the wall thickness of the support portion beinggreater than the wall thickness of the tissue engagement portion. Insuch a device the support portion may also include one or more supportmembers, such as Nitinol rings or the like. In some embodiments, thetissue engagement portion is adapted to temporarily form a seal with thepyloric valve upon contacting the tissue adjacent the valve, and thetissue engagement portion is sufficiently compliant to avoid causingdamage to the tissue on contacting it.

In various embodiments, the obstruction device may have any suitabledimensions, configurations or the like. In one embodiment, for example,the support portion in the second configuration has a widestcross-sectional diameter of between 2.5 cm and 15 cm. The supportportion and tissue engagement portion, in one embodiment, have acombined volume in the second configuration greater than 200 cc. Thiscombined volume, in some embodiments, is sufficient to allow the deviceto act as a space occupying device (as well as a pyloric valveobstructing device) for treating obesity. In addition to its dimensions,the specific gravity or buoyancy of the device may enhance its abilityto contact and obstruct the pyloric valve. In one embodiment, forexample, the device has a specific gravity of between 0.25 and 4.0. Someembodiments may include one or more chambers for introducing a gas orfluid to adjust the buoyancy of the device, or other mechanisms foradjusting buoyancy.

As mentioned, the support portion and tissue engagement portion may haveany suitable shape in various embodiments. In some embodiments, forexample, the device may have an overall cross-sectional shape of acircle, ellipse, triangle, diamond, rectangle, square, star,combinations thereof or the like. In one embodiment, for example, thedevice may have an oblong or tubular shape. In some embodiments, thedevice is hollow, with one or more openings to allow passage of stomachcontents in and out of the hollow portion. In another embodiment, thedevice is cone-shaped, with the tissue engagement portion disposedtoward an apex of the cone and the support portion disposed toward abase of the cone. Another embodiment may be shaped like a cup. As willbe described further below, a number of suitable alternatives ispossible in various embodiments.

Some embodiments of the device also include a positioning memberextending from the tissue engagement portion and having a shape adaptedto pass at least partially through the pyloric valve to position thedevice over the pyloric valve. In one embodiment, the device furtherincludes an inner plug and a compliant outer shell. The shell is movablefrom a first configuration in which it overlaps at least part of thepositioning member to a second configuration in which it overlaps atleast part of the plug. In this embodiment, the plug and a first portionof the shell in the second configuration act as the support portion, anda second portion of the shell in the second configuration acts as thetissue engagement portion. In one embodiment, the shell in the secondconfiguration is generally cone-shaped. The outer shell may be made ofany suitable material(s), but in one embodiment it comprises a materialsuch as Gore-tex®, silicone, polyeurethane or polyethylene, with thewall thickness of the first portion being greater than the wallthickness of the second portion. The thicker first portion provides someof the support function, while the thinner second portion provides thetissue engagement function. In some embodiments, the outer shell ismovable from the first configuration to the second configuration byapplying force to the shell with a distal end of an elongate catheterdevice. Also in some embodiments, the inner plug may be solid and mayhave a largest cross-sectional diameter of at least 10 mm.

Some of the embodiments including a positioning member may furtherinclude a retaining member coupled with a distal end of the positioningmember for maintaining the device in intermittent contact with thepyloric valve. In some embodiments, the retaining member self-expandsfrom a first configuration to a second configuration. Such aself-expanding retaining member may expand within the stomach or withinthe duodenum, in various embodiments. In some embodiments, the retainingmember and the obstructing member are in fluid communication through thepositioning member. A cross-sectional diameter of the retaining membermay be either smaller or larger than a cross-sectional diameter of thesupport portion in the second configuration, according to variousembodiments.

In various embodiments, the retaining member may include any of a numberof different features. For example, in one embodiment the retainingmember includes at least one hole, ring, loop or other surface featurefor attaching a removal device, for removing the obstructing device fromthe stomach. In one embodiment, the retaining member includes at leastone radiopaque marker or material for facilitating visualization of thedevice. In some embodiments, the retaining member is adapted to deliverat least one therapeutic or diagnostic agent to an intestine distal tothe pyloric valve. For example, the retaining member may include adegradable material carrying the therapeutic or diagnostic agent.Alternatively, the retaining member may include one or more housings forreleasably containing the therapeutic or diagnostic agent. In otherembodiments, the therapeutic or diagnostic agent comprises a coatingover at least part of the retaining member. In some embodiments, theretaining member includes an imaging device for imaging an intestinedistal to the pyloric valve. The retaining member may also include achemical measuring device for measuring levels in an intestine of atleast one of lipids, sugars, alcohols, drugs, pH levels, pancreaticsecretions, biliary secretions and/or other dietary or physiologicalchemicals.

A retaining member and/or a positioning member having certain dimensionsmay be advantageous in various embodiments. For example, in oneembodiment a retaining member has a cross-sectional diameter of between0.5 cm and 3.0 cm. In some embodiments, the positioning member has alength of at least 3.0 cm. In some embodiments, the positioning memberhas a cross-sectional diameter of 2 cm or less. The positioning membermay have a general shape adapted to permit the device to intermittentlymove into and out of contact with the pyloric valve, such as acylindrical shape or the like. In some embodiments, the positioningmember is adapted to self-expand from a first diameter to a largersecond diameter within the pyloric valve. In some embodiments, a distalend of the positioning member is weighted.

In a number of embodiments, the device is deliverable into the stomachthrough an esophagus with the support portion in the firstconfiguration. In some embodiments, for example, a biodegradablecovering is disposed over at least the support portion, the coveringbeing adapted to constrain the support portion in the firstconfiguration for delivery into the stomach and to degrade in thestomach to release the support portion from constraint. Whetherincluding such a cover or not, in some embodiments the device is adaptedto be swallowed by a patient with the support portion in the firstconfiguration. Such a swallowed device may further include a retainingcord removably coupled with the device and adapted to extend from thedevice through the patient's esophagus to the patient's mouth. The cordmay retain the device in the stomach until it expands from a firstconfiguration to a second configuration, and then may be removed toallow the obstructing device to contact the pylorus. Optionally, thecord may provide for removal of the device if it does not properlydeploy in the stomach. In some cases, the cord may be swallowed and maydissolve in the patient's stomach.

In other embodiments, the device may removably couplable with anendoscope, an orogastric tube or any other suitable elongate deliverydevice for delivery of the device to the stomach through the esophagus.In some embodiments, the device is adapted to be delivered through alumen of a tube extending from the mouth through the esophagus into thestomach. Optionally, the support portion may be collapsible from thesecond configuration to the first configuration for removal of thedevice through the esophagus. Alternatively, the device may comprise oneor more biodegradable materials so as to degrade over time and passthrough the pyloric valve and the rest of a digestive system. Suchbiodegradable materials may include but are not limited to cellulose,polyethylene glycol, collagen, polylactic acid and/or other polymers.

The device as a whole may include any of a number of various features invarious embodiments. For example, in one embodiment the support portionand/or the tissue engagement portion may include one or more radiopaquematerials, dyes and/or markers. One embodiment may further include oneor more therapeutic or diagnostic agents releasably coupled with thedevice for release within the stomach. Optionally, some embodimentsinclude an imaging device coupled with the obstructing device forimaging the stomach, the pyloric valve, and/or the intestine distal tothe pyloric valve. Some embodiments may include a chemical measuringdevice coupled with the obstructing device for measuring levels in thestomach of lipids, sugars, alcohols and/or the like. Some embodimentsmay include a space occupying member coupled with the obstructing devicefor occupying space in the stomach to treat obesity. Some embodimentsmay include one or more electrodes coupled with the device and removablyattachable to stomach tissue. In such embodiments, a power source forapplying energy to the electrodes, as well as other features, may behoused within the device. Electrodes may be coupled with the device viaone or more cords or tethers.

In another aspect of the invention, a device for obstructing a pyloricvalve of a stomach comprises an obstructing member adapted to expand inthe stomach from a first configuration to a larger second configurationand a positioning member extending from the obstructing member. Asdescribed above, the positioning member has a shape adapted to pass atleast partially through the pyloric valve to position the obstructingmember over the pyloric valve. In some embodiments, the obstructingmember self-expands from the first configuration to the secondconfiguration.

In some embodiments, the obstructing member comprises an inner plug anda compliant outer shell. The shell is movable from a first configurationin which it overlaps at least part of the positioning member to a secondconfiguration in which it overlaps at least part of the plug. The plugand a first portion of the shell in the second configuration act as thesupport portion, and a second portion of the shell in the secondconfiguration acts as the tissue engagement portion. The inner plug andouter shell may have any of the features already described. The deviceas a whole may also have any of the features described above, in variousembodiments. For example, some embodiments further include a retainingmember as previously described.

In another aspect of the invention, a system for obstructing a pyloricvalve of a stomach includes a pyloric valve obstructing device and adelivery device for delivering the pyloric valve obstructing device tothe stomach through the esophagus. The pyloric valve obstructing deviceincludes an expandable support portion adapted to expand in the stomachfrom a first configuration to a larger second configuration and acompliant tissue engagement portion coupled with the expandable supportportion and adapted to engage stomach tissue adjacent the pyloric valvesuch that the device at least intermittently obstructs the pyloricvalve. This obstruction device may optionally be self-expanding and mayinclude any of the other features described above in variousembodiments.

In some embodiments, the delivery device comprises an elongate flexiblecatheter. For example the flexible catheter may comprise an endoscope,an orogastric tube or the like in various embodiments. In someembodiments, the flexible catheter defines a lumen in which theobstructing device is housed during delivery. Such a flexible cathetermay optionally further include a coupling mechanism for releasablyholding the obstructing device within the lumen during delivery. Thedelivery device may also be adapted to remove the obstructing devicefrom the stomach through the esophagus, in some embodiments. In analternative embodiment, the device may be delivery in a collapsed statealongside an endoscope.

In alternative embodiments, the delivery device comprises abiodegradable caplet for containing the obstructing device to allow itto be swallowed by a patient, the biodegradable caplet dissolving withinthe stomach. In these or other embodiments, the obstructing device maycomprise one or more biodegradable materials so as to degrade over timeand pass through the pyloric valve and the rest of a digestive system.Such biodegradable materials may include but are not limited tocellulose, polyethylene glycol, collagen, polylactic acid and/or otherpolymers.

In some embodiments, the system further includes a space occupyingmember coupled with the obstructing device for occupying space in thestomach to treat obesity.

In another aspect of the present invention, a method for obstructing apyloric valve of a stomach involves delivering a pyloric valveobstructing device through an esophagus to the stomach and releasing theobstructing device in the stomach to allow it to expand from a firstconfiguration to a larger second configuration. As has been describedabove, the obstructing device in the second configuration is adapted toat least intermittently contact and obstruct the pyloric valve.

In some embodiments, releasing the obstructing device involves releasingthe device from constraint to allow it to self-expand from the firstconfiguration to the second configuration. For example, the obstructingdevice may be delivered to the stomach via an elongate flexiblecatheter, tube or scope advanced through an esophagus. In otherembodiments, releasing the obstructing device involves allowing apatient to ingest the obstructing device in its first configuration. Insome embodiments, for example, the device may be folded or compressedfor swallowing, with the device unfolding or expanding upon arrival inthe stomach. In another embodiment, delivering the device involvesallowing the patient to ingest a biodegradable capsule containing theobstructing device in the first configuration, the biodegradable capsuledegrading in the stomach to allow expansion to the second configuration.

Although some methods involve releasing a self-expanding obstructingdevice, other embodiments may involve actuating the expansion, using oneor more delivery devices. For example, in some embodiments the methodfurther involves inflating the obstructing device within the stomachbefore releasing it. Further details of inflatable obstructing devicesand methods for their use can be found in U.S. patent application Ser.No. 10/671,191, of which the present application is acontinuation-in-part and which was previously incorporated by reference.In alternative embodiments, the method may further involve moving anexpandable shell of the obstructing device from a first position to asecond position to expand the obstructing device from its firstconfiguration to its second configuration. For example, in oneembodiment the shell may be invert from a position facilitating deliveryof the device to a position for obstructing the pyloric valve, using adistal end of a catheter delivery device. In some methods, it may alsobe possible to adjust buoyancy of the obstructing device before or afterreleasing it to allow it to migrate naturally within the stomach tocontact and obstruct the pyloric valve. Adjusting the buoyancy, forexample, might involve introducing a fluid or a gas into one or morechambers of the device.

In many, if not all, embodiments, delivery of an obstructing device isreversible. Reversibility may be achieved by a number of differenttechniques. In one embodiment, for example, the method for obstructingthe pyloric valve further involves collapsing the obstructing devicefrom the second configuration to the first configuration and removingthe obstructing device from the stomach through the esophagus. Analternative embodiment involves cutting the obstructing device intomultiple pieces and removing the obstructing device from the stomachthrough the esophagus. In either of these embodiments, the delivering,releasing, collapsing and removing steps may in some cases be achievedvia one or more elongate flexible catheters, tubes or scopes advancedthrough an esophagus. In other embodiments, releasing the obstructingdevice in the stomach causes the device to begin to degrade. In suchembodiments, reversibility is achieved by the device degrading over timeand passing harmlessly through the digestive tract.

In some embodiments, the method further includes maintaining theobstructing device in at least intermittent contact with the pyloricvalve by providing the device with a portion that extends at leastpartially through the pyloric valve. In some embodiments, a firstportion of the obstructing member expands from the first configurationto the second configuration in the stomach, and a second portion of theobstructing member passes through the pyloric valve into adjacentintestine before expanding from the first configuration to the secondlarger configuration. Optionally, a bridging portion may extend betweenthe first and second portions, through the pyloric valve, which mayexpand within the stomach or the pyloric valve.

The method may include additional features, such as visualizing at leastone radiopaque marker or material of the obstructing device. In someembodiments, multiple radiopaque markers may be used to visualize theorientation of the device. In some case, the entire device is made of aradiopaque material. In another embodiment, the method includesacquiring one or more images of the stomach, the pyloric valve and/orthe intestine, using an imaging device coupled with the obstructingdevice. In some embodiments, the obstructing member has a size in itssecond configuration that is sufficiently large as to act as aspace-occupying device for further treating obesity. In otherembodiments, the method may further involve expanding a space-occupyingmember coupled with the obstructing member within the stomach to furthertreat obesity.

In yet another aspect of the present invention, a method for obstructinga pyloric valve of a stomach involves passing a pyloric valveobstructing device in a first configuration through a lumen of anelongate catheter device extending through an esophagus to the stomach,advancing the obstructing device at least partially out of a distal endof the catheter device, and expanding the obstructing device from thefirst configuration to a second larger configuration using the catheterdevice. In one embodiment, for example, expanding the obstructing deviceinvolves inverting a compliant shell covering part of the device from afirst, collapsed configuration to a second, expanded configuration,using a distal portion of the catheter device. Optionally, the methodmay further involve releasing the obstructing device from the catheterdevice.

These and other aspects and embodiments of the present invention aredescribed in further detail below, with reference to the drawingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C show cross-sectional views of one variation of a pyloriccorking device designed to partially and/or intermittently obstruct agastric opening in an unexpanded, partially unexpanded, and fullyexpanded configuration, respectively.

FIGS. 2A to 2D show side views of variations of the device utilizingocclusion members of different shapes.

FIGS. 3A to 3C show cross-sectional views of another variation of thepyloric corking device.

FIG. 4A shows a side view of yet another variation of the device havinga tapered bridging member.

FIG. 4B shows a side view of yet another variation of the device havingconical occlusion members held at a distance from one another.

FIGS. 5A and 5B show side views of yet another variation of the devicehaving a single occlusion member and alternative anchor members.

FIGS. 6A to 6C show cross-sectional views of the stomach and onevariation for nasogastric (or endoscopic) placement of a non-ingestiblevariation of the device.

FIGS. 7A to 7C show cross-sectional views of the stomach and anothervariation for nasogastric (or endoscopic) placement of a non-ingestiblevariation of the device.

FIGS. 8A to 8D show cross-sectional views of the stomach and yet anothervariation for placement of a variation of the device through ingestion.

FIGS. 9A to 9D show cross-sectional views of the stomach and yet anothervariation for placement of another variation of the device throughingestion.

FIGS. 10A to 10D show cross-sectional views of the stomach and onevariation for removal of the device.

FIGS. 11A and 11B show top and perspective views, respectively, of analternative variation of the device incorporating multiple prongsdesigned to intermittently obstruct the pyloric valve.

FIGS. 12A and 12B show side and top views, respectively, of anothervariation of the device incorporating multiple prongs designed tointermittently obstruct the pyloric valve.

FIGS. 13A to 13D show cross-sectional views of an alternative use of thedevice for preventing gastroduodenal reflux during tube feeding.

FIGS. 14A to 14D show cross-sectional views of an alternative use of thedevice in combination with one or several gastric fillers.

FIGS. 15A to 15D show cross-sectional views of a device designed topartially displace intragastric volume and intermittently obstruct agastric opening, according to one embodiment of the present invention.

FIG. 16 shows a cross-sectional view of a device as in FIGS. 15A to 15Dwith a rupture.

FIG. 17A shows a cross-sectional view of a device having a positioningmember and a retaining member, according to one embodiment of theinvention.

FIG. 17B shows a cross-sectional view of a device having a positioningmember with an inflation port, according to one embodiment of theinvention.

FIGS. 18A and 18B show cross-sectional views of two differentembodiments of a device for obstructing a pyloric valve, according totwo embodiments.

FIGS. 19A and 19B show side views of an device for obstructing a pyloricvalve, according to another embodiment.

FIGS. 20A to 20C illustrate a method for delivering and deploying thedevice of FIGS. 19A and 19B.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A to 1C are cross-sectional views showing the expansion,respectively, of one variation of a pyloric corking device which isdesigned to partially and/or intermittently obstruct a gastric opening,particularly the pyloric valve. In this particular variation, FIG. 1Aillustrates the device 4 in an unexpanded or uninflated state and readyfor delivery and/or insertion into the pyloric valve. FIG. 1B shows thedistal occlusion member 14 in an expanded state. In use, once the device4 has been placed, e.g., in the pyloric region or beyond, the distalocclusion member 14 (or “retaining member”) may be inflated through theinflux of any number of biocompatible fluids or gases, e.g., saline,water, air, nitrogen, etc., through the tubing 8 leading to theinflation port 6, which may be self-sealing. Tubing 8 may include anynumber of delivery tubes such as catheters, endoscopes, etc.

The distal occlusion member 14 may be configured to inflate before theinflation of proximal occlusion member 16 by fabricating the inflatablemember of distal occlusion member 14 with a material which is moreeasily distensible relative to a material of the proximal occlusionmember 16. Materials which may be used in fabricating the occlusionmembers 14, 16 may include any number of materials such as silicone,silicone elastomers, latex, polyurethane, PTFE, FEP, etc. Alternatively,self-expanding materials, such as foam or hydrogels which typicallyexpand upon contact with fluids, may be utilized within the occlusionmembers 14, 16. If such self-expanding materials are utilized, they maybe disposed in the occlusion member 14, 16 and a fluid such as saline,may be infused to expand the materials. Different self-expandingmaterials may be incorporated in the distal occlusion member 14 than inthe proximal occlusion member 16 to obtain differing radial pressuresexerted by the expanding materials.

In yet another alternative, an expanding scaffolding may be utilizedwithin each of the occlusion members 14, 16. Such a scaffold may be madeof a shape memory alloy or super-elastic alloy, such as Nitinol. Thescaffold may be compressed into a delivery configuration and then eitherallowed to expand into the desired occlusive shape by self-expansion orby supplying an activation energy, e.g., electrical, heat, RF energy,etc. In either case, the distal occlusive member 14 may be positioneddistal of the pyloric valve and then inflated or expanded into itslarger configuration. It may then be pulled proximally against thepyloric annulus, at which point proximal occlusive member 16 may beinflated or expanded by infusion through port 6, as shown in FIG. 1C.With both occlusion members 14, 16 inflated or expanded, bridging member10 connecting the two may span the pylorus. Bridging member 10 may be ofvarious diameters, such as 1 mm and less, which does not significantlyobstruct the pyloric sphincter, up to 8-10 mm in diameter, which doestypically obstruct the pyloric sphincter, or any other suitablediameter.

Bridging member 10 may be designed to have a flexible length sufficientto allow the occlusion members 14, 16 to maintain its position withrespect to the pyloric valve yet still enable the members 14, 16 tomove. Proximal occlusion member 16 may move from fully obstructing thepyloric valve to moving proximally of the pyloric valve to the extentthat distal occlusion member 14 allows member 16 to move. This movementmay be elicited by the natural movements of the gastric lumen (stomach)and muscles surrounding the pyloric valve. Thus, when proximal occlusionmember 16 is moved proximally, the pyloric valve is only partiallyobstructed and may allow for the intermittent passage of food betweenthe bridging member 10 and the valve. Because any food within thestomach is retained for longer periods of time, feelings of satiationmay be initiated sooner and prolonged so that the patient consumes lessfood. Moreover, to allow for the relative movement of the occlusionmembers 14, 16, bridging member 10 may be of a length which issufficient to allow for its placement through the pyloric valve (orthrough another gastric opening) such that there is sufficient tolerancefor the occlusion members 14, 16 to move proximally and distallyrelative to the pyloric valve. For instance, in the event that apatient's pyloric valve extends about 2 cm in length, the bridgingmember 10 is preferably longer than 2 cm, for example, up to 8 cm inlength. Moreover, while occlusion members 14, 16 are inflatable orexpandable, bridging member 10 itself may be configured to inflate orexpand in diameter.

A visible dye or marker, preferably being highly visible, may optionallybe infused into one or both of the occlusion members 14, 16 to functionas a safety measure. Alternatively, one or both of the occlusion members14, 16 may optionally be fabricated from a material which is highlyvisible and visually distinct from tissue so that in the unlikely eventof an occlusion member 14, 16 rupturing, the dye or pieces of theocclusion member 14, 16 may become visible once passed from the body.This may indicate to the patient or physician that a rupture of thedevice has occurred.

Another variation may incorporate slow-releasing drugs infused into thematerials covering the device or materials incorporated into the device.These drugs, which may be any number of drugs, may slowly infuse intothe patient by drug release into the intestinal tract or through contactwith the patient. Alternatively, the devices may incorporate electricalstimulation technologies. For instance, electrical probes may extendfrom a surface of the device for insertion into the surrounding tissueor electrodes may be formed over a surface of the device instead.

In yet another alternative, the occlusion members 14, 16 may be coveredby an erodable or biodegradable covering over one or both members 14,16. Such a covering may be configured to constrain one or both members14, 16 and once the device has been ingested or placed within thegastric lumen, contact with the surrounding fluids may naturally erodethe covering thus allowing the covered occlusion member to expand orinflate. In another variation, proximal and distal occlusion members mayeach be covered by different materials each configured to erode atdiffering rates or in different environments, as described in furtherdetail below.

In the variation shown in FIGS. 1A to 1C, the device 4 may include anoptional lumen 18 defined through the device 4. Optional lumen 18 mayallow for the passage of fluids and food through the device 4 enteringthe lumen 18 through entry port 2 and exiting through the exit port 20.The lumen 18 may be designed to allow for the passage of a reducedvolume of food through the device 4, in which case the device 4 shownmay be configured with a relatively shortened bridging member 10 toinhibit the relative movement of the device 4 relative to the pylorus.With this variation, the lumen 18 has been configured so that it may becapable of actively pumping or metering the contents of the gastriclumen 74 into the intestine 76 through the device 4. In such a case, theneed for the device 4 to be able to move to un-occlude the pyloric valveis removed. As shown in the figures, an optional pump or active meteringvalve 12 may be incorporated into the device 4. Pump or valve 12 may beconfigured to simply open and allow for the passage of the stomachcontents through lumen 18 and valve 12 upon sensing the presence offoreign objects, such as food, in the stomach or upon sensing apredetermined pressure from the contents. Other sensing parameters mayinclude temperature and pH levels. Alternatively, the pump or valve 12may be configured to actively pump the stomach contents through thelumen 18 via a pumping mechanism automatically activated by pump orvalve 12 or externally activated by the patient or physician throughwireless communication. In the case where the device is configured witha valve 12, the valve may be configured as a unidirectional valve toallow the flow of fluids and food only from the stomach to theintestinal tract.

The device 4 could have any shape provided that the shape and/or totalvolume of the proximal occlusion member 16 is sufficient to prevent itspassage through the pyloric valve and into the intestines. FIGS. 2A to2D show side views of different shape variations which are possible foruse as occlusion members. For instance, FIG. 2A shows a side view of adevice variation 22 in which proximal and distal occlusion members 24,26 have a cross-sectional shape along a longitudinal axis defined by thedevice 22 in the form of circles, to form spherical occlusion members.Although proximal and distal occlusion members 24, 26 are illustratedhaving equally sized diameters, the diameters may be varied dependingupon the desired shape and device configuration. For instance, proximalocclusion member 24 may be configured to have a diameter larger thandistal occlusion member 26. Alternatively, a device having the oppositeconfiguration may also be utilized, although this may be lesspreferable. Lumen 28 and pump or valve 12 may be optionally included,again depending upon the desired device configuration.

FIG. 2B shows another device variation in which proximal and distalocclusion members 30, 32 may have a cross-sectional shape along alongitudinal axis defined by the device in the form of ellipses, to formellipsoids. The major axes of the elliptically-shaped occlusion members30, 32 are preferably oriented perpendicularly relative to thelongitudinal axis of the device in this variation, although variousangles may be formed as well. FIG. 2C shows the variation in whichproximal and distal occlusion members 34, 36 may be formed as triangles,to form conically-shaped occlusion members. In this variation, bridgingmember 38 may be minimal in length and may simply be formed by theintersection of the occlusion members 34, 38 to form a waist region.FIG. 2D shows yet another variation in which proximal and distalocclusion members 40, 42 may be formed as diamond shapes, to form avariation of conically-shaped occlusion members. This variation may alsoform a waist region 44.

Although these variations show specific shapes, these are merelyintended to be illustrative of the various types of shapes which may beutilized and is not intended to be limiting. For instance, any shape,such as rectangles, squares, etc., which may function to occlude agastric opening and prevent the device from falling therethrough may beutilized and are within the scope of this disclosure. Moreover, variouscombinations of the different shapes as occlusion members on a singledevice may also be utilized, such as a device having a distal occlusionmember in the shape of a sphere and a proximal occlusion member in theshape of a cone.

FIGS. 3A to 3C show cross-sectional views of another variation of apyloric corking device which is also designed to intermittently obstructa gastric opening. Similar to the device shown in FIGS. 1A to 1C, thisparticular variation omits the use of a lumen defined through the entiredevice 46. This device 46 may also incorporate any of the featuresdescribed above for expanding the occlusion members. For instance, foamof varying expansion pressures may be utilized to ensure that expansionoccurs in the distal occlusion member 50 prior to expansion in theproximal occlusion member 48 upon the injection of a fluid, e.g., salineor water, into the device 46. The device 46 is configured so that theinflux of fluids from the infusion tubing 8 through the entry port 6 ischanneled through the lumen 52 of the central portion from the proximalocclusion member 48 to the distal occlusion member 50. The device 46 mayalso be placed in the same manner as a device as in FIGS. 1A to IC, asdescribed in further detail below. This variation may also incorporatean inflation port 6, which may be metallic, so that removal of thedevice 46, if necessary, can be accomplished through the simpleplacement of a magnetically tipped suction catheter. The catheter, whenappropriately placed, may cause the device to deflate by applying asuction force to facilitate the easy removal of the device 46 from thepyloric valve. The device 46 can thus be removed through any endoscopicor percutaneous approach, e.g., an oro- or nano-gastric approach. Whilethis variation may have a lumen 52 connecting the proximal 48 and distal50 occlusion members, this lumen 52 may be closed to gastric space andinstead be used to communicate an inflation fluid to inflate theocclusion members 48, 50. The occlusion members of the device 46 mayhave any shape as described above, for instance in FIGS. 1A to 2D.

Yet another variation of the device is shown in FIG. 4A. In thisvariation, the device 54 may have a bridging member 60 which is tapered.The bridging member 60 may be tapered to become wider along its lengthfrom the distal occlusion member 58 to the proximal occlusion member 56.The tapered bridging member 60 may be utilized to facilitate movement ofthe device 54 to un-occlude the pyloric valve. As the pyloric valvecontracts about the bridging member 60, the taper may aid in moving thedevice proximally. The angle of the taper may be varied, depending uponthe desired results, as may the size and shapes of the occluding members56, 58.

FIG. 4B shows another variation similar to that shown above. In thisvariation, the device 55 may have occlusion members 57, 59 havingconically-shaped members which are connected via a bridging member 61.This bridging member 61 may have a length which holds occlusion members57, 59 at a distance from one another sufficient to enable the device 55to move relative to the pyloric valve. The device 55 may inflate orexpand the occlusion members 57, 59 using any of the methods disclosedherein and the device 55 may also optionally incorporate a central lumenand a passive or active valve or pumping mechanism, if desired.

In another embodiment, the distal occlusion member may be omittedentirely. FIG. 5A, for instance, shows a side view of an alternativevariation 62 in which the bridging member 66 (or “positioning member”)may extend at some length, e.g., 5 cm or greater, from a proximalocclusion member 64. The bridging member 66 may be placed within theintestinal tract, e.g., the duodenum, while held in place by theproximal occlusion member 64 abutting the pyloric valve. The positioningof the proximal occlusion member 64 relative to the pyloric valve may bemaintained by the frictional forces generated by the bridging member 66rubbing against the walls the intestinal tract. The occlusion member 64may function in the same manner as described above in intermittentlyun-occluding the pyloric valve during stomach contractions and movement,but may be held in place by the length of the bridging member 66.Although the distal end of the bridging member 68 may be free-floatingin the intestinal tract, it may optionally be weighted by a weight 68 orby a number of hooks or barbs 72 for attachment to the intestinal walls,as shown in the device 70 of FIG. 5B.

It is furthermore within the scope of this disclosure that certainfeatures between the different device variations described herein may beincorporated into various combinations. For instance, a device having aproximal occlusion member having a spherical shape and a distalocclusion member having a conical shape may be utilized. As a furtherexample, this device may also incorporate various methods to inflate orexpand the distal occlusion member in a different manner as the proximalocclusion member. Moreover, this device may also have a biodegradablecovering over only one occlusion member and may also incorporate thevalve and/or pump integrated within the device and may also optionallyinclude a lumen defined throughout the length of the device. Theseexamples are merely intended to be illustrative of the variouscombinations which may be employed by combining various aspects fromdifferent variations described herein and are intended to be within thescope of this invention.

FIGS. 6A to 6C show cross-sectional views of the stomach and onevariation for nasogastric (or endoscopic) placement of a non-ingestible,active variation of the device 4. As the device 4 is delivered throughthe esophagus 78, it may be in a compressed, un-inflated, or un-expandedconfiguration, as shown in FIG. 6A, while being positioned via theoptional tubing 8. Once the device 4 has been positioned to span thepylorus with the occlusion members in the stomach 74 and duodenum 76,respectively, the device 4 may be inflated or expanded using any of themethods described above, as shown in FIG. 6B. The tubing 8 may then bedetached and the device 4 left in place, as shown in FIG. 6C.

FIGS. 7A to 7C show cross-sectional views of the stomach and anothervariation for nasogastric (or endoscopic) placement of a non-ingestible,passive variation of the device 46. As above, the device 46 may beadvanced through the esophagus 78 while in a compressed, un-inflated, orun-expanded configuration, as shown in FIG. 7A. As shown in FIG. 7B,once the device 46 has been placed spanning the pylorus with theocclusion members in the stomach 74 and duodenum 76, respectively, thedevice may be inflated or expanded and the tubing 8 may be detached andthe device 46 left in place, as shown in FIG. 7C.

FIGS. 8A to 8D show cross-sectional views of the stomach and yet anothervariation for placement of a passive (or “self-expanding”) embodiment ofthe device 80. As shown in FIG. 8A, the device 80 may be simplyingested. As it enters the stomach 74, gastric fluids may erode an acidsensitive coating over the inflation port of the proximal occlusionmember 82. Once the coating has degraded, the proximal occlusion member82 may be configured to expand or inflate, as shown in FIG. 8B. Once theexpansion or inflation has occurred, the device 80 will remain in thestomach 74 and eventually the distal occlusion member 84 may pass intothe duodenum 76 while still in its un-expanded or un-inflated state dueto the natural contractions of the stomach, as shown in FIG. 8C. Oncethe distal occlusion member 84 has passed into the duodenum 76, analkaline sensitive coating over the distal occlusion member 84 may beeroded and expansion or inflation of the distal occlusion member 84 willoccur with the device spanning the pyloric valve, as shown in FIG. 8D.The covering over the distal occlusion member 84 may be configured toerode only once it has contacted the acidic environment specific to theduodenum 76, where the pH level is approximately 6. In order tofacilitate removal, the two occlusion members 82, 84 may be connected bya central, hollow lumen 86, as described above, with a barrier 88designed to rupture upon the application of a predetermined pressurelevel. Thus, with application of a vacuum having the appropriatepressure level, the barrier 88 may be configured to rupture and theentire device 80 may be deflated.

FIGS. 9A to 9D show cross-sectional views of the stomach and yet anothervariation for placement of a passive variation of the device 90 throughingestion. In this alternative variation, the device 90 can be ingestedorally. As the device 90 enters the stomach 74, shown in FIG. 9A, boththe proximal and distal occlusion members 82, 92, respectively, may beconfigured to inflate upon erosion of acid-sensitive coatings over theinflation port or device 90, as shown in FIGS. 9B and 9C. Once inflationor expansion has been accomplished, the distal occlusion member 92 willeventually be passed due to its smaller size (approximately the diameterof the dilated pyloric valve 5-15 mm) while the proximal occlusionmember 82 will remain in the stomach 74 due to its larger size, e.g., 15mm or greater in diameter and up to 60 mm in diameter due to physiologiclimitations in the pyloric region of the stomach, as shown in FIG. 9D.Thus, one occlusion member 92 may be designed to be small enough to bepassed through the pyloric valve while the proximal occlusion member 82may be designed to be retained in the stomach 74 with both occlusionmembers 82, 92 inflating in the stomach 74.

A number of different alternatives and variations may be employed inself-expanding or “passive” pyloric valve obstructing devices andmethods such as those just described. In some embodiments, a device maybe folded, compressed or otherwise formed into a smaller configurationfor swallowing by a patient, without using a biodegradable coating. Uponpassing through the esophagus into the stomach, the folded device mayunfold due to one or more shape-memory Nitinol support rings or otherself-expanding support members. In any swallowing embodiment, a devicemay also include a tether that extends from the device, back through theesophagus to the patient's mouth. Such a tether may be used forretaining the obstructing device in the stomach until it expands,retrieving the obstructing device if it does not deploy as desired inthe patient's stomach and/or the like. In some embodiments, the tethermay be swallowed to dissolve in the stomach. In other embodiments, aswallowed device may contact the pyloric valve but not include abridging member for spanning the valve. Other variations arecontemplated within the scope of the invention, according to variousembodiments.

FIGS. 10A to 10D show cross-sectional views of the stomach 74 showingone variation for removal of the device 80 (passive variationillustrated). The device 80 is shown in FIG. 10A between the stomach 74and the duodenum 76. As seen in FIG. 10B, a magnetic tipped suctioncatheter or endoscope 94 is introduced and the device 80 may be deflatedand removed, as shown in FIGS. 10C and 10D. In contacting the inflationport 6 with the catheter 94, the tip may be configured with anelectrical contact as an aid in determining whether the catheter 94 hasproperly contacted the inflation port 6. Alternatively, the device 80may be removed through endoscopy or it may be designed to degrade overtime and eventually be passed through the intestines.

In other embodiments, an obstruction device may be removed by deflatingor collapsing the device and removing it through a lumen of a catheterdevice. In one embodiment, the device may be cut into small pieces andremoved through a catheter lumen. in yet another embodiment, the devicemay dissolve over time and pass harmlessly through the pyloric valve andthe digestive system. Any number of suitable alternatives for removal orpassage of the device are possible in various embodiments.

FIGS. 11A and 11B show top and perspective views, respectively, of analternative variation for the device which may reside solely in thestomach. This particular variation may incorporate multiple prongs 100,102, 104, 106, 108, 110 designed to intermittently cork the pylorus. Inthis variation, an expansile material 96 may be appropriately shaped inorder to promote occlusion of the pylorus. The device may be ejectedfrom the pylorus due to contractions, but may be re-inserted through oneof the various prongs. As a further measure, the device may definemultiple apertures 98 through each set of prongs to prevent completeobstruction of the pyloric valve.

FIGS. 12A and 12B show side and top views, respectively, of anothervariation of A device as in FIGS. 11A and 11B. In this variation, afewer number of multiple prongs 112, 114, 116, 118 may be utilized andeach prong may also define an aperture 120 therethrough. However, asshown in this variation, each of the prongs may be flexible and taperedor rounded to prevent damage to the surrounding tissue.

FIGS. 13A to 13D show cross-sectional views of an alternative use of thedevices described herein. In this variation, the device may be utilizedin the prevention of gastroduodenal reflux during tube feeding. Asshown, the device 124 is similar to variations described above; however,in this variation, a lumen 132 defined through the device 124 for tubefeed delivery may define an outlet 134 designed to be positioned in theduodenum 76. The proximal portion of the device 124 may also be attachedto a feeding tube 126 and an inflation tubing 130. Feeding tube 126 maybe used to deliver tube feeds through the lumen 132 directly to theduodenum 140 while the inflation tubing 130 may be used to inflate aninflatable pyloric spanner or bridging member 136 during tube feeding toprevent reflux of delivered material 140. The device 124 can alsoincorporate a third tube 128 which may provide for aspiration of thegastric contents 138 to prevent reflux of the delivered material intothe lungs and to decompress the stomach 74. The proximal portion of theocclusive member can either maintain its inflated or expanded state orit can be decompressed at times to relieve pressure on the pyloricvalve. In this variation, a percutaneous approach is shown, but anasogastric approach or another approach is possible.

FIGS. 14A to 14D show cross-sectional views of yet another alternativeuse of devices of the present invention. As shown in FIGS. 14A to 14C, adevice 90 may be placed to occlude the pyloric valve. In this case, thedevice 90 is shown as having been ingested, although placement of thedevice 90 may be affected via any of the methods described above. Asshown in FIG. 14D, the addition of one or several gastric fillers 142,e.g., inflatable gastric balloons, expandable scaffolding, or any othernumber of space-occupying devices generally known in the art, may beutilized. In this variation, the device 90 may be placed and then thegastric fillers 142 may be introduced. The device 90 may be utilized toensure that the gastric fillers 142 are not passed through the pyloricvalve until they are sufficiently small, thereby allowing fornon-degradable substances to be utilized without the concomitant risk ofsmall bowel obstruction.

FIGS. 15A to 15D are cross-sectional views demonstrating the use ofanother embodiment of a device 150 for intermittently obstructing apyloric valve 156, and in this embodiment for partially filling thegastric space. FIG. 15A illustrates the device 150 in an unexpanded oruninflated state and ready for delivery and/or insertion into thestomach via a catheter device 152, such as an endoscope, tubing or thelike. The device, in this embodiment, includes an expandable foam 154,which is expanded when the device 150 is within the stomach, as shown inFIG. 15B. Any suitable nontoxic liquids or gases may be introducedthrough an inflation port 158, for expanding the device 150 and/or thefoam 154.

Any suitable materials may be used to form the device 150. In oneembodiment, for example, the device 150 may comprise an expandableballoon fabricated from silicone, silicone elastomers, latex,polyurethane, PTFE, FEP, and/or the like. Alternatively, self-expandingmaterials, such as foam or hydrogels which typically expand upon contactwith fluids, may be utilized within the device 150. If suchself-expanding materials are utilized, they may be disposed in thedevice 150, and a fluid such as saline may be infused to expand thematerials.

As shown in FIG. 15B, the device 150 in one embodiment includes aproximal portion 153 and a distal portion 155. In some embodiments, theproximal portion 153 has a supportive or structural function, forassuring that the device 150 has a large enough cross sectional diameterto prevent passage of the device 150 through the pyloric valve.Typically, the distal portion 155 functions to contact the pyloric valve156 and/or tissue adjacent the pyloric valve 156, to intermittentlyand/or partially block the valve 156. In some embodiments, the distalportion 155 is made of compliant material, so that when it contactsstomach tissue in, around or adjacent the pyloric valve 156, it does notharm the tissue. In some embodiments the proximal portion 153 and distalportion 155 are made of the same material, with the proximal portion 153having a greater amount of material, greater wall thickness or the like,relative to the distal portion 155.

Generally, the device 150 may have any of a number of suitable shapes,such as an irregular oblong shape as shown, an elongated sphericalshape, a cone, a diamond or the like. In some embodiments, the shape isselected such that the device 150 naturally migrates toward the pyloricvalve 156, with the distal portion 155 aligned to contact the valve 156.In these and other embodiments, migration of the device 150 to the valve156 may be further enhanced by selecting a specific gravity or buoyancyof the device to allow it to move through the stomach contents towardsthe valve 156.

FIGS. 15C and 15D the distal portion 155 of the device 150 ininteracting with the pyloric valve 156. As illustrated, the shape of thedistal portion 155 is configured to move out of (FIG. 15C) and into(FIG. 15D) contact with the valve 156. This typically occurs during thenatural contractions of the stomach, thus providing for intermittentobstruction of the pyloric valve 156. Intermittent obstruction of thepyloric valve 156 causes food in the stomach to be retained longer, andthus, feelings of satiation may be initiated sooner and may last longer,leading the patient to consume less food. In the embodiment shown inFIGS. 15C and 15D, the distal portion 155 fully obstructs the valve 156when it is in contact. In alternative embodiments, the distal portion155 may not fully obstruct the valve 156 and may have any of a number ofvarious configurations designed to allow partial flow even when fullycontacting the pyloric valve 156. For example, the distal portion 155may have a shape such as conical, ellipsoid, spherical, pyramidal,tubular, disc-shaped with a protruding member (designed to fit withinthe pylorus) or the like. In one embodiment, the distal portion 155 andthe proximal portion 153 have identical or nearly identical shapes, sothat either end may obstruct the pyloric valve 156, regardless of theorientation of the device 150.

The device 150 may have any of a number of additional features forenhancing its delivery into the stomach, it ability to intermittentlyobstruct the pyloric valve 156, its removal from the stomach and/or thelike. In one embodiment, for example, the device 150 includes one ormore radiopaque markers, dyes and/or materials for facilitatingvisualization of the device 150. The device 150 may also include othermarkers, dyes or materials that enhance its visibility to the naked eye,which may be advantageous in embodiments where the device 150 dissolvesand passes through the body or as a safety feature in the unlikely eventthat the device 150 breaks or ruptures.

In some embodiments, the device 150 may include one or more mechanismsfor releasing one or more drugs into the stomach or small intestinebeyond the pyloric valve. For example, slow-releasing drugs may becoupled with or infused into materials covering the device 150 ormaterials used to construct the device 150. These drugs, which may beany of a number of therapeutic or diagnostic agents, may slowly infuseinto the patient by drug release into the intestinal tract or throughcontact with the patient. In other embodiments, the device 150 mayincorporate electrical stimulation technologies. For instance,electrical probes may extend from a surface of the device 150 forinsertion into the surrounding tissue or electrodes may be formed over asurface of the device 150.

In one embodiment, the device 150 may be covered by an erodable orbiodegradable covering for delivery into the stomach. Such a coveringmay be configured to constrain the device 150, and once the coveringcomes into contact with substances in the gastric lumen, it maynaturally break down and dissolve, thus releasing the device 150 andallowing it to expand. In one embodiment, the device 150 may be coveredby different materials each configured to erode at differing rates or indifferent chemical environments within the stomach.

FIG. 16 illustrates the device 150 of FIGS. 15A to 15D, in which arupture 157 has occurred. As demonstrated by this figure, the overallshape of the device 150 is maintained due to expanded foam 154 (or otherframework material or the like within or on the device 150 in otherembodiments). Generally, the foam or framework material will beacid-resistant in order to prevent its degradation within the stomachand thus allow it to support the device 150 for extended periods of timeafter rupture has occurred. In an alternative embodiment, the foam 154or other framework material may degrade slowly after rupture whilereleasing a signaling material that would alert the patient to therupture upon examination of feces. The patient would then know toconsult his physician to have the device 150 removed.

Referring now to FIGS. 17A and 17B, another embodiment of a pyloricvalve obstructing device 160 may include and inflation port 168, aproximal portion 163, a distal portion 165, a positioning member 161 anda retaining member 162. Inflation port 168 is optional, of course, sincesome embodiments require inflation while others do not. Positioningmember 161 generally helps position the device 160 in a location forintermittently obstructing the pyloric valve 156. Retaining member 162helps maintain the location or position of the device 160.

In one embodiment, the positioning member 161 may be hollow, thusallowing for passage of fluids and/or gases through the device to allowthe proximal portion 163, distal portion 165 and retaining member 162 tobe inflated. In one embodiment, positioning member 161 may be relativelyshort, to inhibit movement of the distal portion 165 relative to thepylorus 156. In other embodiments, the positioning member 161 may belonger to allow for more movement of the device 160.

Referring now to FIG. 17B, in another embodiment a device 170 havingproximal 173 and distal 175 portions is coupled with a positioningmember 171 that includes an inflation port 172 at its distal end. Inthis embodiment, the device 170 is passed to the stomach in itsuninflated state, the positioning member 171 and port 172 are used toinflate the device 170, and the positioning member is then swallowed andpasses through the pyloric valve 156 to remain harmlessly in the firstpart of the small intestine. In another embodiment, the device may beplaced into the stomach while attached to a removable tether thatextends up the esophagus and into the mouth. The tether can be used toremove the device if it does not properly deploy, or alternatively itcan be detached from the device once it is in place in the stomach.

As illustrated in FIGS. 18A and 18B, and as mentioned earlier, variousembodiments of a device for obstructing a pyloric valve may include anyof a number of different expandable support mechanisms. The embodimentsjust described included foam, but other supportive structures andmaterials may be used, such as self-expanding cages, coils, lattices,frameworks or the like. In FIG. 18A, a device 180 having proximal 183and distal 185 portions as well as an inflation port 188 also includesan expanding scaffolding 184, which may be coupled with the wall of thedevice 180 on its inner surface or outer surface, or which may beembedded in the wall. Such an expanding scaffolding 184 may be composedof shape memory or super-elastic materials, such as Nitinol. Thescaffold 184 may be compressed into a delivery configuration and theneither allowed to expand into the desired occlusive shape byself-expansion or expanded by supplying an activation energy, such as,electrical energy, heat, RF energy or the like. In another embodiment,the scaffold may be deployed by pulling the scaffold into an expandedconfiguration with a pulling device, and in such embodiments thescaffold may have a catch mechanism to prevent it from collapsing to itsoriginal shape.

In the embodiment shown in FIG. 18B, a device 190 includes a proximalportion 193, a distal portion 195 and an inflation port 198. In thisembodiment, a wall 194 of the device 190 is made of a shape memory,super-elastic or otherwise self-expanding material, which expands from asmaller configuration to a larger configuration upon release fromconstraint. The material of the wall 194 then retains its expandedshape, thus maintaining the shape of the device 190 and preventing thedevice from collapsing.

Referring to FIGS. 19A and 19B, another embodiment of a pyloric valveobstructing device 200 includes a movable or “inverted” outer shell 204,an inner core 202, a positioning member 208 and a distal retainingmember 210 having a hole 212 or other surface feature. The device 200 isshown in its expanded configuration in FIG. 19A, for intermittentlyobstructing a pyloric valve, and in its collapsed configuration in FIG.19B, for delivery into the stomach. The shell 204 includes a tissuecontacting/engaging portion 205 and a support portion 206. Generally,the support portion 206 is more rigid/stiffer than the tissue contactportion 205, so that the former helps maintain the cross-sectionaldiameter of the device 200 so that it cannot pass through the pylorus,while the latter is more compliant so that it can contact stomach tissuewithout causing significant damage.

The various components of the device 200 may be constructed of anysuitable materials, such as those already described or any othersuitable materials now known or hereafter discovered. In one embodiment,the inner core 202 is a solid material, such as silicone, but in otherembodiments the core 202 may be hollow. The core 202 may have anysuitable size, shape, cross-sectional diameter or the like. In oneembodiment, the core 202 has a cross-sectional diameter of between about5 mm and about 30 mm, and preferably about 10 mm. The shell 204 may bemade of the same or different material as the core 202, and also mayhave any suitable size, shape, cross-sectional diameter or the like. Inone embodiment, the support portion 206 of the shell 204 is thicker thatthe tissue contact portion 205. In other embodiments, the supportportion 206 may be made of a different material than the tissue contactportion 205.

The positioning member 208 may be an extension of inner core 202, shell204 or both, or may instead be a separate piece coupled with the innercore 202 and/or outer shell 204. Positioning member 208 may have anysuitable length and diameter to allow it to pass through the pyloricvalve. In one embodiment its cross-sectional diameter is about 1.0 cm orless and its length is about 3.0 cm or greater. The retaining member 210may also have any suitable size, shape or configuration, with someembodiments being expandable, some being self-expanding, and othersconfigured to not expand at all. In one embodiment, the retaining member210 has a greatest cross-sectional diameter of about 30 mm or smaller,and preferably about 25 mm or smaller, and even more preferable about 21mm or smaller. The hole 212 or surface feature in the retaining member210 may have any configuration for allowing coupling of an actuator orother device with the retaining member for delivering, adjusting and/orretrieving the device 200. Both the positioning member 208 and theretaining member 210 may be made of any suitable material.

Although not drawn to scale, FIG. 19B illustrates the collapsed orinverted state of the device 200. In this configuration, the shell 204may be compressed to a smaller cross-sectional diameter for delivery,such as through a delivery tube or catheter. After the device 200 isdelivered to the stomach, the shell 204 is inverted to its expandedstate and the device 200 may then act to intermittently obstruct thepyloric valve.

FIGS. 20A to 20C illustrate a method for delivering and deploying thedevice 200 of FIGS. 19A and 19B in a stomach. In FIG. 20A, the device200 is housed within the lumen of a delivery tube 214 or catheter in itscollapsed configuration. In FIG. 20B, the device has been advancedpartially out of the delivery tube, allowing the shell 204 to at leastpartially expand. An actuator 216 hooked through the hole 212 on theretaining member 210 may then be used to pull back on the device 200,such that the shell 204 overlaps the distal end of the delivery tube214. The distal end of the delivery tube 204 is then used to apply forceto the shell 204, causing it to invert into its expanded state, as shownin FIG. 20C. As also shown in FIG. 20C, the actuator 216 may include ahook 218 for coupling with the hole 212 in the retaining member 210.Once the shell 204 is moved to its expanded configuration, it isdesigned to stay in that configuration, thus providing the pyloric valvecontacting and device retention functions described above. In oneembodiment, the delivery tube 214 may include an expandable balloon (notshown) at or near its distal end. The balloon maybe doughnut-shaped toinflate circumferentially, or may be have an eccentric shape or anyother suitable shape. The balloon may be inflated and serve as a stopagainst which the device 200 may be pulled. Alternatively, the balloonmay be inflated under or within the device 200 to invert the device 200as the balloon inflates.

In other embodiments, the device may be delivered and/or deployed usingany other suitable method. For example, in one embodiment the shell 204may “self-invert” from its constrained/collapsed state to its expandedstate without using an actuator 216 or the distal end of a deliverydevice 214. Self-inverting may be achieved by shape-memory or springloaded materials or the like, or by a shell geometry that creates a biasin the stiffness of the device. In another embodiment, the device 200may be swallowed, either in a folded or otherwise collapsed state orhoused within a dissolving caplet. A number of different alternativeembodiments are possible.

Although the above is a complete and accurate description of theinvention, any of a number of variations, additions and the like may bemade to the embodiments described without departing from the scope ofthe invention. For example, devices and methods described above are notlimited strictly to treatment of obesity, but may also be used to treatother conditions. Furthermore, other devices, such as imaging devices,chemical detection devices, space occupying devices and/or the like maybe incorporated into many of the embodiments described above withoutdeparting from the scope of the invention. Therefore, the foregoingdescription is provided primarily for exemplary purposes and should notbe interpreted to limit the scope of the invention as it is defined inthe following claims.

1. A device for obstructing a pyloric valve of a stomach, the devicecomprising: an expandable support portion adapted to reconfigure in thestomach from a first configuration to a larger second configuration,wherein the support portion in the second configuration is sized toprevent passage of the device through the pyloric valve; a complianttissue engagement surface comprising a compliant outer shell which isformed external to the expandable support portion when in the largersecond configuration such that the surface surrounds an inner plugwithin a hollow portion formed within the support portion and whereinthe surface is adapted to be intermittently engaged to stomach tissueadjacent the pyloric valve whereby the pyloric valve is intermittentlyobstructed; a tubular positioning member having a length extending fromthe tissue engagement surface and having a shape adapted to pass atleast partially through the pyloric valve to position the device overthe pyloric valve, where the outer shell is movable from a firstconfiguration in which it overlaps at least part of the positioningmember to a second configuration in which it overlaps at least part ofthe plug; and a retaining member having a diameter larger than thepositioning member and coupled with a distal end of the positioningmember for maintaining the device in intermittent contact with thepyloric valve, where the retaining member has an atraumatic shape.
 2. Adevice as in claim 1, wherein the expandable support portion comprisesat least one self-expanding material.
 3. A device as in claim 2, whereinthe at least one self-expanding material is selected from the groupconsisting of spring stainless steel, shape-memory materials,super-elastic materials and spring-loaded materials.
 4. A device as inclaim 2, wherein the self-expanding material comprises a self-expandingfoam disposed within at least one of the expandable support portion andthe tissue engagement surface.
 5. A device as in claim 4, wherein thefoam comprises at least one of polyethylene foam, polyurethane foam andsilicone foam.
 6. A device as in claim 2, wherein the self-expandingmaterial expands upon contacting one or more substances present in thestomach.
 7. A device as in claim 1, wherein the tissue engagementsurface is adapted to temporarily form a seal with the pyloric valveupon contacting the tissue adjacent the valve, and wherein the tissueengagement portion is sufficiently compliant to avoid causing damage tothe tissue on contacting it.
 8. A device as in claim 1, wherein thesupport portion in the second configuration has a widest cross-sectionaldiameter of between 2.5 cm and 15 cm.
 9. A device as in claim 1, whereinthe support portion and the tissue engagement portion have a combinedvolume in the second configuration greater than 200 cc.
 10. A device asin claim 1, wherein the device has a specific gravity of between 0.25and 4.0.
 11. A device as in claim 1, wherein the device has an overallcross-sectional shape selected from the group consisting of a circle, anellipse, a triangle, a diamond, a rectangle, a square, a star of acombination thereof.
 12. A device as in claim 1, wherein the device iscone-shaped, with the tissue engagement portion disposed toward an apexof the cone and the support portion disposed toward a base of the cone.13. A device as in claim 1, wherein the outer shell comprises a materialselected from the group consisting of silicone, polyeurethane andpolyethylene.
 14. A device as in claim 13, wherein the outer shell ismovable from the first configuration to the second configuration byapplying force to the shell with a distal end of an elongate catheterdevice.
 15. A device as in claim 13, wherein the inner plug is solid.16. A device as in claim 1, wherein the retaining member self-expandsfrom a first configuration to a second configuration.
 17. A device as inclaim 16, wherein the retaining member is adapted to expand within thestomach.
 18. A device as in claim 1, wherein a cross-sectional diameterof the retaining member is smaller than a cross-sectional diameter ofthe support portion in the second configuration.
 19. A device as inclaim 18, wherein the cross-sectional diameter of the retaining memberis about 30 mm or less.
 20. A device as in claim 1, wherein theretaining member includes at least one hole, ring, or loop for attachinga removal device.
 21. A device as in claim 1, wherein the positioningmember has a length of at least 3.0 cm.
 22. A device as in claim 1,wherein the positioning member has a cross-sectional diameter of 2 cm orless.
 23. A device as in claim 1, wherein the shape of the positioningmember is further adapted to permit the device to intermittently moveinto and out of contact with the pyloric valve.
 24. A device as in claim1, wherein the positioning member is adapted to self-expand from a firstdiameter to a larger second diameter within the pyloric valve.
 25. Adevice as in claim 1, wherein the device is deliverable into the stomachthrough an esophagus with the support portion in the firstconfiguration.
 26. A device as in claim 25, wherein the device isremovably couplable with an elongate device for delivery of the deviceto the stomach through the esophagus.
 27. A device as in claim 25,wherein the device is adapted to be delivered through a lumen of a tubeextending from a mouth through the esophagus into the stomach.
 28. Adevice as in claim 25, wherein the support portion is collapsible fromthe second configuration to the first configuration for removal of thedevice through the esophagus.
 29. A device as in claim 25, wherein thedevice comprises one or more biodegradable materials so as to degradeover time and pass through the pyloric valve and the rest of a digestivesystem.
 30. A device as in claim 29, wherein the biodegradable materialsare selected from the group consisting of cellulose, polyethyleneglycol, collagen, and polylactic acid.
 31. A device for obstructing apyloric valve of a stomach, the device comprising: an obstructing memberadapted to reconfigure in the stomach from a first configuration to alarger second configuration which is sized to prevent passage of thedevice through the pyloric valve, wherein the obstructing memberpresents a surface comprising a compliant outer shell when in the largersecond configuration which surrounds an inner plug within a hollowportion formed within the obstructing member and which intermittentlyengages stomach tissue adjacent the pyloric valve whereby the pyloricvalve is intermittently obstructed; a tubular positioning member havinga length extending from the obstructing member, the positioning memberhaving a shape adapted to pass at least partially through the pyloricvalve to position the obstructing member over the pyloric valve, wherethe outer shell is movable from a first configuration in which itoverlaps at least part of the positioning member to a secondconfiguration in which it overlaps at least part of the plug; and, aretaining member having a diameter larger than the positioning memberand coupled with a distal end of the positioning member for maintainingthe device in intermittent contact with the pyloric valve, where theretaining member has an atraumatic shape.
 32. A device as in claim 31,wherein the obstructing member self-expands from the first configurationto the second configuration.
 33. A device as in claim 31, wherein theouter shell comprises a material selected from the group consisting ofsilicone, polyeurethane and polyethylene.
 34. A device as in claim 33,wherein the outer shell is movable from the first configuration to thesecond configuration by applying force to the shell with a distal end ofan elongate catheter device.
 35. A device as in claim 33, wherein theinner plug is solid.
 36. A device as in claim 31, wherein the retainingmember self-expands from a first configuration to a secondconfiguration.
 37. A system for obstructing a pyloric valve of astomach, the system comprising: a pyloric valve obstructing devicecomprising: an expandable support portion adapted to reconfigure in thestomach from a first configuration to a larger second configuration,wherein the support portion in the second configuration is sized toprevent passage of the device through the pyloric valve; a complianttissue engagement surface comprising a compliant outer shell which isformed external to the expandable support portion when in the largersecond configuration such that the surface surrounds an inner plugwithin a hollow portion formed within the support portion and whereinthe surface is adapted to be intermittently engaged to stomach tissueadjacent the pyloric valve whereby the pyloric valve is intermittentlyobstructed; and, a tubular retaining member having a length coupled tothe tissue engagement surface where the retaining member has anatraumatic shape, where the outer shell is movable from a firstconfiguration in which it overlaps at least part of the retaining memberto a second configuration in which it overlaps at least part of theplug; and a delivery device attachable to a coupling feature along theobstructing device for delivering the pyloric valve obstructing deviceto the stomach through an esophagus.
 38. A system as in claim 37,wherein the support portion is adapted to self-expand from the firstconfiguration to the second configuration within the stomach.
 39. Asystem as in claim 37, wherein the delivery device comprises an elongateflexible catheter.
 40. A system as in claim 39, wherein the flexiblecatheter defines a lumen in which the obstructing device is housedduring delivery.
 41. A system as in claim 40, wherein the flexiblecatheter further comprises a coupling mechanism for releasably holdingthe obstructing device within the lumen during delivery.
 42. A system asin claim 41, wherein the delivery device is adapted to remove theobstructing device from the stomach through the esophagus.
 43. A systemas in claim 37, wherein the obstructing device comprises one or morebiodegradable materials so as to degrade over time and pass through thepyloric valve and the rest of a digestive system.
 44. A system as inclaim 43, wherein the biodegradable materials are selected from thegroup consisting of cellulose, polyethylene glycol, collagen, andpolylactic acid.